Automatic layer picking assemblies for a warehouse suitable for composing mixed layer pallets are for example known from AU2010/235933 (Robotic Automation, 2011), US2008/0267759 (Axium, 2008) and US2008/0008573 (California Natural Products, 2008). These assemblies generally comprise a layer transporter in the form of a robotic arm mounted on a pallet transporter that transports a destination pallet along a plurality of source pallets. During the mixing operation, first the pallet transporter needs to position the destination pallet in close proximity of the source pallet from which a pallet layer needs to be transferred to the destination pallet. Subsequently the robotic arm mounted on the pallet transporter executes a layer transfer operation by positioning its layer picking device at the source pallet, picking a pallet layer from this source pallet, positioning this pallet layer at the destination pallet and placing this pallet layer on the destination pallet. The throughput of such an automatic layer picking assembly is limited by several factors. The inertia of the pallet transporter is relatively large as it needs to transport the destination pallet and the robotic arm, this limits the maximum acceleration and thus also the maximum velocity of the pallet transporter during the mixing operation. Furthermore scalability of such a system is limited as each of the pallet transporters requires a dedicated layer transporter.
An alternative system for producing mixed layer pallets is for example known from US2007/0280814 (Axium, 2007). Such a system comprises a pallet layer transporter, in the form of a robotic arm with a suitable gripper, that decomposes the source pallets and stores its products in an intermediate buffer. Subsequently the destination pallets comprising pallet layers, each comprising different products originating from different source pallets, is compiled by the pallet layer transporter from the products stored in this intermediate buffer. The throughput of such a system is limited by the fact that all destination pallets must be decomposed in their entirety into the intermediate buffer and it is clear that the need for such an intermediate buffer and the associated space requirements, puts limits on the scalability of such a system.
Therefor there still exists a need for an improved automatic layer picking assembly that is able to overcome the above mentioned drawbacks and is able to achieve a simple and efficient setup allowing for improvements relating to throughput and scalability.